Loading boom construction



Oct. 23, 1951 E, HALL LOADING BOOM CONSTRUCTION Filed Sept. 50, 1947 IINKYIENTOR. -fl/eri E, ha/l flTTORNEYS Patented Oct. 23, 1951 UNITED STATES PATENT OFFICE LOADING BOOM CONSTRUCTION Albert E. Hall, Hamilton, Wash. Application September 30, 1947, Serial No. 776,947 4 Claims. (Cl. 21259) My invention relates to a boom construction employed in loading and unloading. When used in connection with dog leg booms, my invention provides bracing of the dog leg boom to minimize the size and weight of the dog leg boom proper.

Heretofore dog leg booms have been used in connection with loading booms, shovels, cranes, and the like but because of the inherent weakness of the boom at the bend, massive dog leg booms were employed.

It is an object of my invention to provide a construction wherein a dog leg boom of a minimum weight and mass may be employed.

Heretofore in structures employing either straight or dog leg booms, it was necessary to employ a high mast which made the structure have a substantial height even though the boom was in a lower position.

It is an object of my invention to provide a link construction which moves up and down as the boom moves up and down and thus provides for a minimum overall height of the construction when the boom is down.

Heretofore where dog leg booms were employed very substantial strains were placed on the bend of the boom and horizontally on the pivotal connection between the dog leg boom and the cab or carriage.

It is an object of my invention to lessen and counteract the strain at the bend and thus provide for minimum mass and weight, and to change the horizontal thrust on the pivotal connection to the cab to a vertical thrust-a vertical thrust is useful in stabilizing the cab. In this connection devices embodying my invention have successfully employed dog leg booms weighing in the neighborhood of two tons which will do the same work as prior art construction requiring a dog leg boom weighing in the neighborhood of six tons.

The above mentioned general objects of my invention together with others inherent in' the same are attained by the devices illustrated in the accompanying drawings throughout which like reference numerals indicate like parts:

Figure 1 is a plan view of a construction illustrating a use of my invention in connection with a log loader device, parts of the structural bracing being eliminated in order to better illustrate novel features of my invention;

Fig. 2 is a view in side elevation of the construction shown in Fig. 1 and again some of the structural bracing is removed for the same reason that the same was removed in Fig. 1, also in Fig. 2 I have illustrated by dot and dash line another position which the parts may assume and I have illustrated a log as the load being carried; and

Fig. 3 is a somewhat diagrammatic fragmentary view of a modified form of my invention.

Referring to the drawings, I have illustrated my invention as applied to one of the standard types of mobile cabs. The standard parts will be caterpillar mobile unit 3 rotatably mounting the cab deck or base casting 4. The cab deck or base casting 4 mounts vertical supports 5 which in turn mount the topping sheave shaft 6. The topping sheave shaft 6 is braced by diagonal supports 1 and connected with base casting or deck ,4. The base casting or deck 4 provides suitable boom heel pins 8. This much of the construction may follow prior art practices and the construction described is illustrative of an environment in which my invention is applicable.

A dog leg boom comprises the main boom portion 9 and the dog leg portion ID. The heel of the boom 9-H] is pivotally supported on boom 7 heel pins 8. The dog leg boom 9-40 is preferably fabricated from a plurality of structural members but as fabrication of dog leg booms from a plurality of structural member is old, only parts of the fabrication are illustrated and other parts have been broken away.

Links H are pivoted on the topping sheave shaft 6 and links H are pivotally connected with other links !2, which links [2 are pivoted to the dog leg boom and substantially in alignment with the bend between the main boom portion 9 and the dog leg portion Ill. The pivotal means between the links H and I2 comprises a cross shaft l3 or two spaced pin means.

In the form of my invention shown in Figs. 1 and 2, a cable connection is provided between an outer' end of the main boom portion 9, over cross shaft l3, and over topping sheave shaft 6. 'As an illustration thereof and of a construction providing substantial leverage, I have indicated a boom hoist cable l4 connected at one end portion to the base casting or deck 4 by means of a thimble I5. The said cable l4 passes upwardly and over a sheave l6 mounted on the topping sheave shaft 6. Viewed in Fig. 2 said cable l4 passes over and around sheave l6 in a clockwise direction. Thence the cable l4 passes over and around sheave I! in a clockwise direction. Sheave I1 is rotatably mounted on cross shaft l3. Next, the cable l4 passes over and around a sheave I8 in a clockwise direction. Sheave I8 is mounted on a spreader or carriage l9. Spreader I9 is connected with the outer end of the main boom portion 9 by cables 20 and thimbles 2|. While the cable l4 may be connected directly with the outer end of the main boom portion 9 this is not essential and cable is saved by the use of the spreader l9 and cables 20.

The cable l4, after passing around sheave IS in a clockwise direction, is led to a sheave 22 carried by a purchase block assembly 23. The purchase block assembly 23 is pivoted on cross shaft l3. The cable l4 then passes around sheave 22 in a clockwise direction and is led to a sheave 24 carried by spreader I9. Next, the cable is reaved about sheave 24 in a counterclockwise direction and is led to a sheave 25 carried by the purchase block assembly 23. Cable I4 is reaved 25 in a clockwise direction and is led to sheave 26 carried by the spreader H5. The cable M is .then reaved about sheave 26 in a clockwise direction and is led to a sheave 2'! carried by the cross shaft I3. The cable is then passed over sheave 2i in a counterclockwise direction and over a sheave 28. Sheave .28 is .carried by topping sheave shaft 5. The cable is then reaved about sheave 23 in a counterclockwise direction and is led to a power driven hoisting drum 29. The cable id is the boom hoist cableand is employed to raise or lower the outer end :of the dog leg boom 9-45 The prime mover and control means for driven drum is are .not indicated as the same may be of conventional construction.

The load hoist cable 3a? is connected with another driven drum 3i and is reaved over a sheave 32 preferablylocated at the bend portion of the dog leg, then about a sheave 33 carried by the outer end portion of the main boom portion '9. As illustrative of a .load on the load hoisting cable 38, I have indicated tongs 34 connected with a log 35. Thus the cable 35 extends substantially parallel to boom portion 9.

With the parts in .the positions shown by full lines in Fig. 2 there will be a compression strain longitudinally of the main boom portion 9. Also the boom hoist cable vill be under tension. At the same time the links 2 will be under compression while links H will primarily be under tension. The compressionstrains present in the main boom portion 9 are counteracted by strains in the cable It ,and links "ii and i2. By actual demonstrations I have established that little of the longitudinal strain in the main boom portion 9 is carried by the boom heel pins n. Thus little bending strain is present between the dog leg portion to and the main boom portion 9 and I am able to eliminate much of the bracing about sheave which was heretofore employed to prevent sep-,

aration of the main boom portion 9 and the dog leg portion H1. The forces resisting compression forces in the links 52 and boom portion E3 will be a longitudinal compression within the dog leg portion Ill. However, this is an advantage as the structural bracing to withstand compression is not in the order of a structural bracing to withstand bending and compression on heel pins 8 tends to stabilize the cab.

One of the most important reasons for the use of a dog leg boom is that the boom will clear objects close to the heel of the boom without requiring the boom at its free end to be too high in the air. However, the disadvantage of dog leg booms has been the inherent weakness about the bend portion forming the dog leg. use of my invention I have been able to eliminate such weak point and eliminate any bending moments between the main boom portion and the With the dog leg portion and at the same time retain all of the benefits of a dog leg boom.

.As will appear by the clot and dash line positions of some of the parts in Fig. 2, links l l and I2 as well as the cross shaft l3 move downwardly as the outer end of the dog leg boom 9| 6 moves downwardly. Thus in transporting the vehicle from place to place, the overall height of the device can be decreased by lowering the outer end of the dog leg boom 9lfl. This is to be distinguished from the prior art construction employing a high mast which high mast was always at the same elevation regardless of the position of the dog leg boom. The angle defined by the cable I :3 as one leg and the main boom.

portion 9 as the other leg must not be too small or the lifting moments on the outer end of the' doglegl'S-J 0, which obtains by drawing in cable M, is too small. Thus as the 'high mast in the prior art devices had a fixed elevation, this elevaition had to be high enough to take care of operations where the outer end of the boom was in its maximum height. As distinguished from this prior art operation, I have in effect provided for an extensible high mast. In my device the cross shaft is is in eiiect the top of the high mast. As the boom 9 rises the cross shaft I3 rises and thus the height of the eifective high mast of my construction rises as the outer end of the boom 9 rises. Thus I have all of the advantages of a. fixed high mast without the disadvantages regarding clearance for the vehicle under overhanging structures. As an example and not as a'limitation, I have provided a construction where the cross shaft I 3 has a range of travel of approximately four feet with a lower elevation of approximately twelve feet. Thus such construction provides the lifting moments of a sixteen foot high mast and with a clearance (when the boom is down) of a twleve foot high mast.

Referring now to the fragmentary view Fig. 3, the. sheavelti is indicated, links H are indicated, a fragment of links I2 is indicated, sheave i8 is indicated, thimbles 21 are indicated, and a fragment of cables 28 is shown. This construction and the parts broken away will be identical with that shown in the previous figures, home only a fragment is shown. The difference between the construction of Fig. 3 and that of Fig.

2 is that another form of moving of the boomhoist cable is shown. The boom hoist cable 3'5 of Fig. 3 passes from sheave it directly to sheave 48 instead of passing from sheave l6 and over sheave ii, to sheave ill. The cable after passing over sheave 8 can in the same manner as was cable 15. Also other forms of reeving of the boom hoist cable may be employed, but Iprefer the construction of Figs. 1 and 2 as when the cable it} passes over sheave l'l, the bight of the line urges sheave ll and in turn cross shaft I3 and parts connected therewith in a downward direction.

While I have illustrated my invention in connection with a log loader it is to be understood that my invention is not limited to such a construction. My invention is applicable to all sta tionary as well as mobile units employing as a part of their equipment a boom. Some of such constructions will be mobile Wreckers for moving automobiles or railroad cars, and loaders :for ships, cars and the like. Also grab buckets, diggers, and other constructions employing loading booms.

Obviously, if the links H and 12 are employed in connection with a straight boom rather than a dog leg boom, the advantage of raising and lowering the fulcrum defined by cross shaft l3 will be present. Thus it is to be understood that the advantage of eliminating the usual high mast by the structure of my invention is not limited to dog leg boom constructions. Similarly, it is to be understood that my invention is not limited to a fabricated metal boom and my invention is particularly useful in connection with wood beam boom structures.

From the foregoing it will be apparent that in my invention I may employ the usual spaced supports which are the topping sheave shaft 6 and the boom heel pins 8. Preferably the support provided by the topping sheave shaft 5 is at a be thereafter reeved our direction of the boom 9l0. The link means l2 which are pivoted to the link means ll extend angularly downwardly toward the said boom and are pivoted to the said boom. The pivotal connection of the link means I2 to the boom 9-H! is outward from the pivotal connection 8 and thus the cross shaft l3 will rise and fall as the outer end portion of the boom 9-40 rises and falls. The cable means l4 or 36 which is used to provide stresses on the links H and I2 so they can brace the boom 9-l0, are connected with an outer portion of the boom, such as the outer end portion thereof as shown, and such cable means I4 is connected with the pivotal connection between links H and I2. This connection between the cable and the pivotal connection provided by cross shaft l3 may be direct as is indicated in Figs. 1 or 2 or indirect as is shown in the modified construction of Fig. 3.

If a dog leg boom is employed preferably the link 12 has its pivotal connection with the boom 9 located at the bend providing the dog leg.

Preferably the load hoisting cable 39 is aligned so that it extends substantially parallel to the boom 9 and if a dog leg boom is employed then preferably I provide sheave 32 at the bend of the dog leg.

Obviously, changes may be made in the forms, dimensions, and arrangements of the parts of my invention without departing from the principle thereof, the above setting forth only preferred forms of embodiment of my invention.

I claim:

1. In load handling mechanism having a base means mounting a first fixed supporting means, a second fixed supporting means spaced forwardly of said first fixed supporting means, and a prime mover, a boom pivoted at one end portion to said second fixed supporting means and extending forwardly from said base means; first link means pivoted to said first fixed supporting means and extending upwardly and forwardly; second link means pivoted at one end portion to said first link means, extending downwardly and forwardly, and pivoted at the other end portion to an inner portion of said boom away from the pivotal connection of said boom to said base means; sheave means carried by said first and second link means at the pivotal connection therebetween, whereby said sheave means raises and lowers with raising and lowering of the outer end portion of said boom; and cable means connected with an outer portion of said boom and with said prime mover and reeved over said sheave means.

2. In load handling mechanism having a base means mounting a first fixed supporting means, a second fixed supporting means spaced forwardly of said first fixed supporting means and at a lower position than said first supporting means, and a prime mover, a boom pivoted at one end portion to said second fixed supporting means and extending forwardly from said base means; a thrust brace between said first and second fixed supporting means; first link means pivoted to said first fixed supporting means and extending upwardly and forwardly; second link means pivoted at one end portion to said first link means, extending downwardly and forwardly, and pivoted at the other end portion to an inner portion of said boom away from the pivotal connection of said boom to said base means; sheave means carried by said first and second link means at the pivotal connection therebetween, whereby said sheave means raises and lowers with raising and lowering of the outer end portion of said boom;

and cable means connected with an outer portion of said boom and with said prime mover and reeved over said sheave means.

3. In load handling mechanism having a base means mounting a first fixed supporting means, a second fixed supporting means spaced forwardly of said first fixed supporting means, and a prime mover, a boom pivoted at one end portion to said second fixed supporting means and extending forwardly from said base means; first link means pivoted to said first fixed supporting means and extending upwardly and forwardly; second link means pivoted at one end portion to said first link means, extending downwardly and forwardly, and pivoted at the other end portion to an inner portion of said boom away from the pivotal connection of said boom to said base means; first sheave means carried by said first and second link means at the pivotal connection therebetween,whereby said first sheave means raises and lowers with raising and lowering of the outer end portion of said boom; second sheave means connected with the outer end portion of said boom and disposed at a location intermediate the length of the boom; and cable means connected with said prime mover and passing over said first and second sheave means.

4. In load handling mechanism having a base mean mounting a first fixed supporting means, a second fixed supporting means spaced forwardly of said first fixed supporting means, and a prime mover, a boom pivoted at one end portion to said second fixed supporting means and extending forwardly from said base means; first link means pivoted to said first fixed supporting means and extending upwardly and forwardly; second link means pivoted at one end portion to said first link means, extending downwardly and forwardly, and pivoted at the other end portion to an inner portion of said boom away from the pivotal connection of said boom to said base means; sheave means carried by said first and second link means at the pivotal connection therebetween, whereby said sheave means raises and lowers with raising and lowering of the outer end portion of said boom; boom lift cable means connected with an outer portion of said boom and with said prime mover and reeved over said sheave means; and a power driven load cable alined substantially with the said boom, passing over the outer end of said boom, and connectable with a load.

ALBERT E. HALL.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 739,955 De Vow Sept. 29, 1903 1,187,699 Bathrick June 20, 1916 1,965,367 Brown July 3, 1934 2,198,793 Schroeder Apr. 30, 1940 2,440,199 Huston Apr. 20, 1948 

